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Facile Synthesis of Mn-Doped ZnO Porous Nanosheets as Anode Materials for Lithium Ion Batteries with a Better Cycle Durability.

Wang L, Tang K, Zhang M, Xu J - Nanoscale Res Lett (2015)

Bottom Line: Porous Zn1 - x Mn x O (x = 0.1, 0.2, 0.44) nanosheets were prepared by a low-cost, large-scale production and simple approach, and the applications of these nanosheets as an anode material for Li-ion batteries (LIBs) were explored.Electrochemical measurements showed that the porous Zn0.8Mn0.2O nanosheets still delivered a stable reversible capacity of 210 mA h g(-1) at a current rate of 120 mA g(-1) up to 300 cycles.These results suggest that the facile synthetic method of producing porous Zn0.8Mn0.2O nanostructure can realize a better cycle durability with stable reversible capacity.

View Article: PubMed Central - PubMed

Affiliation: School College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, P.R. China, wlinlin@mail.ustc.edu.cn.

ABSTRACT
Porous Zn1 - x Mn x O (x = 0.1, 0.2, 0.44) nanosheets were prepared by a low-cost, large-scale production and simple approach, and the applications of these nanosheets as an anode material for Li-ion batteries (LIBs) were explored. Electrochemical measurements showed that the porous Zn0.8Mn0.2O nanosheets still delivered a stable reversible capacity of 210 mA h g(-1) at a current rate of 120 mA g(-1) up to 300 cycles. These results suggest that the facile synthetic method of producing porous Zn0.8Mn0.2O nanostructure can realize a better cycle durability with stable reversible capacity.

No MeSH data available.


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SEM images of the sample A: a low magnification, b high magnification; TEM images: c low magnification and d, e high magnification; (f) a HRTEM image
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Fig3: SEM images of the sample A: a low magnification, b high magnification; TEM images: c low magnification and d, e high magnification; (f) a HRTEM image

Mentions: The XRD pattern of the precursor is shown in Fig. 1a. All of the peaks can be assigned to hexagonal ZnO (JCPDS file No. 89-0511). The chemical composition of the sample A was determined by XRD and XPS. The crystallinity and crystal phase of the sample A were demonstrated by the XRD shown in Fig. 1b. The peaks in the diffraction pattern of Zn1 − xMnxO at 31.81°, 34.43°, and 36.30° can be indexed to a hexagonal wurtzite structure, which consists of three prominent peaks corresponding to (100), (002), and (101) planes, respectively. Compared with the peak position of ZnO (inset), that of Zn1 − xMnxO was found to shift towards lower angles with Mn incorporation, probably due to the larger ionic radius of Mn2+ (0.066 nm) relative to that of Zn2+ (0.060 nm) [20, 21]. The XPS survey spectrum confirms that the sample mainly contains Zn, Mn, and O (Fig. 2). The strong peaks at around 641.7 eV (Fig. 2a) are assigned to Mn2p3/2. The values correspond to a binding energy of Mn2+ ion [21]. The peak at 1022.4 eV (Fig. 2c) is assigned to Zn2p3/2 for the Zn2+ state (Fig. 2b) and the peak at 531.4 eV (Fig. 2c) corresponds to the binding energy of O1s. In addition, the ratio of Mn to Zn of 6.38:25.05 is given by the quantification of peaks, indicating that the molar ratio of Mn to Zn is near 1:4. The above results indicate that the prepared sample A is single phase Zn0.8Mn0.2O. The SEM images (Fig. 3a, b) show that the Zn0.8Mn0.2O samples are sheet-like morphology with many holes in the nanosheets. From the TEM images (Fig. 3c–e), the porous nanosheets were clearly observed, which further confirms the formation of Zn0.8Mn0.2O porous nanostructures. We also examined the phase purity of the resulting powder that has not been calcined by the XRD. From the XRD pattern (Additional file 1: Figure S1 in supporting information), it is clearly seen that the diffraction pattern of the resulting powder are different from the precursor ZnO and Zn1 − xMnxO. This result suggests that the chemical reaction process (Mn-doped ZnO) is not simple zinc substituted by manganese but involves a complex reaction which led to its structure and composition being changed. The structure and composition of the resulting powder is complex and difficult to identify. However, due to the similar XRD pattern of Zn(OH)2 and ZnO, it is reasonable that hydroxide ions might be introduced into the resulting powder during the reaction process, in addition to the possible organic molecules. The morphology of resulting powder (Additional file 1: Figure S2) is nanosheets. Interestingly, after calcination, a number of pores appear on the nanosheets, possibly due to decomposition of the organic molecules and hydroxyl group in the calcination process. The pore size distribution curves have been investigated by using Barrett–Joyner–Halenda (BJH) method. Basing on the report of nitrogen adsorption–desorption shown in Additional file 1: Figure S3, the Zn0.8Mn0.2O exhibited a BET surface area of 41.45 m2 g−1 and adsorption average pore diameter of 8.5 nm. For the Zn0.8Mn0.2O nanosheets, lattice images showed fringes with a spacing of ca. 0.1625 nm and ca. 0.2605 nm, corresponding to the (110) and (002) planes of ZnO (Fig. 3f). An overall schematic model of the synthesis procedure is shown in Fig. 4. The energy dispersion X-ray spectrum (EDS) of the as-prepared sample B and C (Additional file 1: Figure S4) shows that the molar ratio of Mn to Zn of 7.99:66.12 and 16.66:20.96 is near 1:8 (Zn0.9Mn0.1O) and 1:1.25 (Zn0.56Mn0.44O), respectively.Fig. 1


Facile Synthesis of Mn-Doped ZnO Porous Nanosheets as Anode Materials for Lithium Ion Batteries with a Better Cycle Durability.

Wang L, Tang K, Zhang M, Xu J - Nanoscale Res Lett (2015)

SEM images of the sample A: a low magnification, b high magnification; TEM images: c low magnification and d, e high magnification; (f) a HRTEM image
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4489971&req=5

Fig3: SEM images of the sample A: a low magnification, b high magnification; TEM images: c low magnification and d, e high magnification; (f) a HRTEM image
Mentions: The XRD pattern of the precursor is shown in Fig. 1a. All of the peaks can be assigned to hexagonal ZnO (JCPDS file No. 89-0511). The chemical composition of the sample A was determined by XRD and XPS. The crystallinity and crystal phase of the sample A were demonstrated by the XRD shown in Fig. 1b. The peaks in the diffraction pattern of Zn1 − xMnxO at 31.81°, 34.43°, and 36.30° can be indexed to a hexagonal wurtzite structure, which consists of three prominent peaks corresponding to (100), (002), and (101) planes, respectively. Compared with the peak position of ZnO (inset), that of Zn1 − xMnxO was found to shift towards lower angles with Mn incorporation, probably due to the larger ionic radius of Mn2+ (0.066 nm) relative to that of Zn2+ (0.060 nm) [20, 21]. The XPS survey spectrum confirms that the sample mainly contains Zn, Mn, and O (Fig. 2). The strong peaks at around 641.7 eV (Fig. 2a) are assigned to Mn2p3/2. The values correspond to a binding energy of Mn2+ ion [21]. The peak at 1022.4 eV (Fig. 2c) is assigned to Zn2p3/2 for the Zn2+ state (Fig. 2b) and the peak at 531.4 eV (Fig. 2c) corresponds to the binding energy of O1s. In addition, the ratio of Mn to Zn of 6.38:25.05 is given by the quantification of peaks, indicating that the molar ratio of Mn to Zn is near 1:4. The above results indicate that the prepared sample A is single phase Zn0.8Mn0.2O. The SEM images (Fig. 3a, b) show that the Zn0.8Mn0.2O samples are sheet-like morphology with many holes in the nanosheets. From the TEM images (Fig. 3c–e), the porous nanosheets were clearly observed, which further confirms the formation of Zn0.8Mn0.2O porous nanostructures. We also examined the phase purity of the resulting powder that has not been calcined by the XRD. From the XRD pattern (Additional file 1: Figure S1 in supporting information), it is clearly seen that the diffraction pattern of the resulting powder are different from the precursor ZnO and Zn1 − xMnxO. This result suggests that the chemical reaction process (Mn-doped ZnO) is not simple zinc substituted by manganese but involves a complex reaction which led to its structure and composition being changed. The structure and composition of the resulting powder is complex and difficult to identify. However, due to the similar XRD pattern of Zn(OH)2 and ZnO, it is reasonable that hydroxide ions might be introduced into the resulting powder during the reaction process, in addition to the possible organic molecules. The morphology of resulting powder (Additional file 1: Figure S2) is nanosheets. Interestingly, after calcination, a number of pores appear on the nanosheets, possibly due to decomposition of the organic molecules and hydroxyl group in the calcination process. The pore size distribution curves have been investigated by using Barrett–Joyner–Halenda (BJH) method. Basing on the report of nitrogen adsorption–desorption shown in Additional file 1: Figure S3, the Zn0.8Mn0.2O exhibited a BET surface area of 41.45 m2 g−1 and adsorption average pore diameter of 8.5 nm. For the Zn0.8Mn0.2O nanosheets, lattice images showed fringes with a spacing of ca. 0.1625 nm and ca. 0.2605 nm, corresponding to the (110) and (002) planes of ZnO (Fig. 3f). An overall schematic model of the synthesis procedure is shown in Fig. 4. The energy dispersion X-ray spectrum (EDS) of the as-prepared sample B and C (Additional file 1: Figure S4) shows that the molar ratio of Mn to Zn of 7.99:66.12 and 16.66:20.96 is near 1:8 (Zn0.9Mn0.1O) and 1:1.25 (Zn0.56Mn0.44O), respectively.Fig. 1

Bottom Line: Porous Zn1 - x Mn x O (x = 0.1, 0.2, 0.44) nanosheets were prepared by a low-cost, large-scale production and simple approach, and the applications of these nanosheets as an anode material for Li-ion batteries (LIBs) were explored.Electrochemical measurements showed that the porous Zn0.8Mn0.2O nanosheets still delivered a stable reversible capacity of 210 mA h g(-1) at a current rate of 120 mA g(-1) up to 300 cycles.These results suggest that the facile synthetic method of producing porous Zn0.8Mn0.2O nanostructure can realize a better cycle durability with stable reversible capacity.

View Article: PubMed Central - PubMed

Affiliation: School College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Shanghai, 201620, P.R. China, wlinlin@mail.ustc.edu.cn.

ABSTRACT
Porous Zn1 - x Mn x O (x = 0.1, 0.2, 0.44) nanosheets were prepared by a low-cost, large-scale production and simple approach, and the applications of these nanosheets as an anode material for Li-ion batteries (LIBs) were explored. Electrochemical measurements showed that the porous Zn0.8Mn0.2O nanosheets still delivered a stable reversible capacity of 210 mA h g(-1) at a current rate of 120 mA g(-1) up to 300 cycles. These results suggest that the facile synthetic method of producing porous Zn0.8Mn0.2O nanostructure can realize a better cycle durability with stable reversible capacity.

No MeSH data available.


Related in: MedlinePlus